Just like the US Consitution, the Constitution of the CSA does not specifically call out secession (see Article VI, 6) - one of the most sacred rights among the Confederate states. Perhaps they understood what delegating and retaining rights means.
How hard is it to understand? Words that are completely missing ("perpetual", "permanent") can be divined by them in a heartbeat, but the literal and plain meaning of a statment is ignored or overlooked.